Title: The effect of magnesium concentration and deformation on the ageing behaviour of Al-Mg alloys

Authors: Swami Naidu Gurugubelli; A.V.S.S.K.S. Gupta; N.R.M.R. Bhargava

Addresses: Department of Metallurgical Engineering, JNTUK College of Engineering, Vizianagaram, Andhra Pradesh, 535003, India ' Department of Metallurgical Engineering, JNTUK College of Engineering, Vizianagaram, Andhra Pradesh, 535003, India ' Department of Metallurgical Engineering, JNTUK College of Engineering, Vizianagaram, Andhra Pradesh, 535003, India

Abstract: Cylindrical samples of Al-Mg alloys with Mg content 2 to 8 wt% were solution treated at 450°C for two hours and aged at 200°C. The effect of magnesium concentration and deformation on the ageing behaviour of Al-Mg alloys was studied. Dilute Al-Mg alloys were not responded for age hardening due to the insufficient amount of magnesium to form critical fractions of GP zones and coherent precipitates. For higher deformations large amounts of coherent precipitates were not formed during ageing due to the increased activation energy, and hence the peak hardness values were reduced with increased deformation. Mathematical equations were developed for the paths followed by solution treated hardness and peak hardness curves during ageing of the cold worked alloys and extrapolated using MATLAB. Solution treated Al-8Mg alloys deformed to more than 30% resulted in no improvement of the hardness during ageing and it is identified that solution treated Al-8Mg alloys subjected to 30% deformation possess optimum hardness.

Keywords: hardness; aluminium alloys; deformation; magnesium concentration; ageing behaviour.

DOI: 10.1504/IJMATEI.2013.052810

International Journal of Materials Engineering Innovation, 2013 Vol.4 No.1, pp.57 - 64

Received: 15 Mar 2012
Accepted: 04 Oct 2012
Published online: 19 Jul 2014 *

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